I'm making a chevron style baby cot quilt for my grand-daughter but I'm a bit brain fried in working out how much material to use, as the tutorials all use charm packs and baby brain won't let me convert it.

Wanting to use 5" squares, and have found 5 different fabrics (4 variations of purple and then a white for in between the diagonals). Would want finished size approx 40x50"

Won't have a sashing around the outside, just binding. Can anyone help?

each 5 inch square is 2 hst so each square of uncut fabric will need to be 6 inches (2 sets of 1/4 inch seam allowances)
40 inches across with 5 inch squares is 8 across and 50 inches high with 5 inch squares is 10 across so 80 squares total

quilt fabric is about 40 inches across (although some are more) so you can get 6 squares across

half your squares will be white - 40 squares , at 6 across you need 7 rows so 42 inches - about 1.1m
the other half will be purple of four kinds so ten squares of each, at 6 across you need 2 rows so 12 inches - about 30cm.

to allow for shrinkage and straightening the grain on the fabric I'd allow 1.2 m of white and 40cm of each purple.

I have a 5" ruler square so wanting to stick with that size - which would make the finished 'squares' 4.5" right? That's what I was struggling with the most haha

I think if I buy half a metre of all the purples, and 1.5m of the white I should be safe, and then I can just play with the rest to get it to the size I need. Hoping to get into spotty while they still have a good sale on, but of course most of the fabrics she chose arn't in the sale.

You need to work out how you are going to make the triangles. You can cut all the triangles and sew together but have to be very careful sewing on bias. Or you can sew squares together and cut them up....you can do either stitching down middle and create 2 squares or stitch both diagonals and have 4 squares. Does that make sense? Then depending on which way you sew them you need to calculate the size to cut the squares as they need to be a certain size bigger to allow for the technique - there are online conversations to work it out, just need to google it.